Remote control system



Patented Mar. 5, 1946' REMOTE ("JGNTRGE SYSTEM" The Union Switch & Signal Gunman-y,

Swissvale,-Pa.,, a corporation of, Bennsxlvania. ApplicationDecem-ber 17, 1 94 3 Serial No: 514,641 V (c1. m r-ass):-

8v Glaimsc Myinventionrelates to remote control systoms,- and more particularly to centralized traffic control systems for railroads for'the control of railway signals or other trafiic controllingdevices from a central point of control: such as a train dispatchers ofiice; and for'the, indication of such devices or of train movements at the control oflice.

The transmitting portion of the system of my invention is claimed in mydivisionalapplication, Serial No. 561,563; filedv November2, 1944, for Transmitting apparatus for remote control systems.

One object of my invention isthe, provision of a system suitable for the direct control of unattended manual block signals employing" currentsof such-a character that they'maybe transmitted at times over existing railroad" com-mum'- cation circuits without interferingmateriallywith their use for other communication purposes;

Another object of my-invention is the provision of a system for communicating by code between acontrolofi'ice and, a plurality ofremotestations; in which the codes-comprisedifierent sequences of impulses of alternating "currentsof 'diiferent frequencies within a hand of frequencies preferably in the voice frequency range or at least in'a rangewhich is suitable for transmission over existing telephone circuits.

Other objects, features and purposes ofmy invention will he pointed out as the description proceeds;

I shall describe one form of apparatus embodying my invention, and shall then. point out the novel features thereof'in' claims.

Referring to the accompanying drawing, the reference" characters Y and Z designate a pair. of line wires which it is to be understood. provide a telephone circuit extending, from ,a control oflice at which the apparatus atthe left of the drawing is located, through aplurality of stations situated at spaced points alonga stretchffof. raiL' way at each of which stations a, pair'of manual block signals LH and RH islocatedl as indicated by the trackv diagram, eachstation beingv provided with apparatus similar to that. shown at the right of the drawing, having aiconnection to the line wires Y and Z asshown. It may beassumed that the stretch is not provided; with. track circuits except for a short detector section B at each station having a track .itelay for: the control of-the-signalsand for'indicatin theimovements ofv trains past the stationsyand that train movements through the stretch are'governedl prii 55 is: picked up;

bytrain' orders, supplemented by manual control 'o'f-ith signals.

"In-its'specific embodiment; asshown, the system of my inventiondprovides facilities by which the signals at each of ten stations-maybe selectively controlled to give-proceed; permissive 'orstop indi'cations by the lighting of the lamps-G, Y or respectively of the signals and; RH, in response tothe operation of suitable push "buttons PS and" PFat the control 'ofirce, and. also providesmeansrfor lighting selected indication lamps Eat the oflice to indicate whengthe corresponding signals are at stop; each lamp; being lighted automatically-when atra-in enters. the corresponding detectorsection.

The apparatus provided at eachstation includes threeselector-relays-Rl, R2 and R3, three signal control relays LHS, RHS and 'DS, and an indication'transmitting-relay Ll; Atfive 'oft'he stati'ons, adjustable connections are made to contacts a and e-ofrelayRl' to render relay R3 responsive to line signals when relay RI is energized. -At theremainingfive stations; the connections are shiftedto contactsw and c of relay R2 to render relay R3 responsive to line signals when relay R2 is energized. Each selector relay R3 is arranged. to he energized through "a rectifier unit I' l, when the unit is supplied with alternatin current from a tuned circuit comprising a coil l2 and a condenser Ch. Each-such tunedj circuit is adapted topass sufli'cient current to energize the associated relay only when supplied with current of a particular frequency received over the line-wires and Z. In the system as shown,

- the control of tenstations is-contemplatedg, and a band of tenfrequencies ,flto fill is used, five of'which; namely, the frequencies ft to ii, are employed to select the-stations;

In the-drawing, the reference characters fl, f2,

1 etc: indicating the frequency towhich each tuned circuit isresponsive; are; adjacent the circuit: the circuit for relay R3, for example; at, the station shown; being selectively responsive to' the freuuencyfli. a

The relays-'RI and Rzare direct current relays ofthe biased polartype which" respond selectively to the steady component of the current supplied to the line wires 'Y and Z, a reactor 13 being interposed in the line connections, relay- RI respending only when linewire Y positive'and relay' R2" only when line wire- Y is negative; with respect t'o-l'ine wirejZ. At. each of five stations; relay vR31 is arranged to respond to a diiierent one olF-the frequencies fl to 15' provided relay R1 the line connection for the timed circuits including contact a of relay RI as shown. At each of the remaining five stations, relay R3 is responsive to a difierent one of the frequencies fl to f5 provided relay R2 is picked up, its tuned circuit being adjustably connected to contact a of relay R2, and it follows therefore that the relay R3 at any one of the ten stations may be selectively energized by a single impulse of pulsating current having one of two polarities and one of five frequencies.

Each relay R3 is provided with a stick circuit extending from the positive terminal B of a local source of direct currentat the station over contact c of the relay RI or R2 which controls its pick-up circuit, as indicated diagrammatically on the drawing, over the front contact a andlower winding of relay R3 to the negative terminal C of the local source. It follows that relay R3 at a selected station ma be held picked up, along with relay RI or R2, after the alternating current impulse is terminated, provided direct current continues to be supplied to the line. Under these circumstances the tuned circuits for relays DS, LHS and RHS, which are responsive to alternating currents of frequencies f6, fl and f8, respectively, in the same manner as relay R3, are connected to the line over contact a of relay RI or R2 and contact b of relay R3, and if a second impulse of frequency f6, fl or 18 is supplied to the line, relay DS, LHS or RHS may be energized, while if a second impulse of frequency fl or f8 followed by a third impulse of frequenc 16 is supplied to the line, relay LHS or RHS may be energized and relay DS in addition Each of the relays LHS and RHS is provided with a stick circuit including its own front contact a, a back contact of relay R3 and a front contact a of the track relay TR of the detector track section T, consequently if either relay RHS or LHS is energized it may be released manually by operation of relay R3, or automatically by a train entering section T. Relay DS has a stick circuit including its own front contact a and front con? tact c of relay LHS or RHS and consequently will be released along with relay LHS or RHS, if energized. Relays LHS and DS jointly control the lamps R, Y and G for signal LH, and relays RHS and DS similarly control those for signal RI-l in a well-known manner which may be readily ascertained from the drawing.

The station apparatus also includes a source of alternating current of a particular frequency in the band of frequencies f I to 1 I0, which source as shown may be understood to be an electron tube oscillator OSC similar to the one including the tube VT at the office as hereinafter described. The output circuit of oscillator OSC is adapted to be connected to the line wires Y and Z, at times, in response to the operation of relay LI, to indicate that relays LHS and RHS are released and that the signals are consequently at stop. When relays RI or R2, R3 and D3 are operated, relay LHS or RHS will be released by relay R3, if energized, and relay LI picks up over the circuit extending from terminal B at contact 0 of relay uI or R2, front contact a of relay R3, front contact d of relay DS, back contacts (1 of relays LHS and RHS through relay LI to terminal C, and is held energized over the stick circuit including its own front contact a, and extending to terminal B at contact 0 of relay RI or R2. When relay LI is picked up by a control impulse in this manner, its energizing circuit is opened as soon as the line becomes free, as indicated by the release of relay RI or R2 and if relays LHS and RHS are both in their released positions, an impulse of current of a selected frequency in the band fIfI0 will be supplied to the line wires over back contacts e of relays LHS and RHS, front contacts b and c of relay LI, back contacts b of relays RI and R2, coil I5 and condenser C4, the impulse terminating with the release of relay LI, which relay is slow acting. Rela LHS or RHS is released automatically following the release of relay TR by a train, and since relays LHS and RHS are slow to release, as shown, relay LI becomes energized over a circuit closed momentarily which extends from terminal B at back contact a of relay TR, over front contact d of relay LHS or RHS through relay LI to terminal C and the indication impulse will be transmitted during the release period of relay LI following the release of relay LHS or RHS.

It will be seen that since back contacts 11 of both line relays RI and R2 are included in the circuit for transmitting the indication impulse, its transmission cannot occur when the line is in use for transmitting control impulses to any of the ten stations.

At the control office, the indication receiving apparatus includes a set of ten indication relays KI to KID, of which but three are shown, each controlled over a tuned circuit similar to that provided for the station relays but tuned to a different one of the tenfrequencies II to II II. Relay KI, having its circuit tuned to the frequency it, responds vto the indication impulse received from the station shown and is then held energized overa stick circuit until manually released, lighting a lamp E I to indicate that the signals LH and RH at the corresponding station stand at stop.

The office transmitting apparatus includes ten sets of manually operable selecting contacts, controlled by a series of push buttons PS, for select- 40 ing the stations, of which for simplicity but three are shown, namely PSI, PS2 and PSII]; five sets of manually operable control contacts, controlled by another series of push buttons PFI to PF5, inclusive, for governing the signal control relays at the selected station; a set of five relays PC, DR, OR, L andLP for governing the transmission .of the impulses, and an oscillator including the electron tube VT for generating the alternating current of the desired frequencies.

The operation of contact a of any of the push buttons PS opens the stick circuit for the associated indication relay K, and closes a circuit for energizing relay PC, which relay is of the polar stick type and serves as a pole changer to govern the polarity of the direct current supplied to the line from a local source having the terminals B and C, as shown. It is to be understood that the operation of any one of the buttons PI to P5 energizes the upper winding of relay PC to cause it to operate its contacts a and b to the left as shown to render'the relays RI responsive, while the operation of any one of the buttons P6 to PI Il energizes the lower winding of relay PC to cause it to operate its contacts to the right, to

gender the relays R2 responsive to the steady component of the line current. The opening of contact 21 of any of the buttons PS disconnects the circuits controlling the indication relays KI to KID from the line, rendering these relays nonresponsive to the control impulses. The closing of the contact 0 of any of the buttons PS completes a connection from the line wires Y and Z to the output coil I6 for the oscillator VT, through a rectifier I8 and a condenser C5, while theclosing of contact d of the operatedbutton aaearac PS; completes a tunedi circuit: including? coil: l1 and: condenser (it for: controlling the frequency generated by the; electron tube VT; and delivered tow the line by. coil: to. Contacts: dot: buttons. PSttoPSli are each connected to a. different. tap on coil [1: to cause the: generation. oi'ja different one of theirequenciesifl to f5-,. respectively, buttons PS6: to PSI 0: being similarly connected to cause. thee generation of the same frequencies;

Hayingzthusdescribed the various components or the: system of: my invention, I shall. now explain: its mode of operation, assuming first that" with the. apparatus as shown, the operator desires to obtain a recall indication from the sta tion shown to verify: the factthat thesignals are at2stop; Hewill first operate button PSI, releasing relayKl: and thereby cancelling the existing indication displayed by lamp El and operating relay PC to normal, as shown. The oscillator tube VT will'be set into operation to supply cur-- rentto: the line wires of frequency fl over the connection to coil I8 including contact c of button- PSI and rectifier I8 Contacts d of relays RI and- R2 at each station are now open and the alternating current delivered tothe line is principally dueto thecapacity between linewires Y and This, however, is' of a value sufiicient to pick up thedetector relay DR, provided the oscillatordelivers thepropervoltage and its connections to the line wires are intact so as-to include the line capacity in its output circuit. When relayDR picks up, unidirectional current is supplied to the linecircuit including the relays Eland R2, over-the connection from terminals B andC-at contacts a and b of relay PC, contacts I b and c' of relay DR through the direct current relay OR and coil [9 to the line wires Y and Z, thereby picking up relay'OR and also'the relays Rt at all" stations to open their contacts him the indication circuits, and to closetheir contacts a, so that relay R3-- at the selected station also picks up; The closing of contact a of relay OR complet'es acircuit for energizinga chain of' timing relays illustrated by the relays L and LP which pick up successively, the closing" of contact a of relay LP lighting a' control lampCE and cornpleting' alocal stick circuit for relay DR; It'will be noted that the tuned circuit including coil l1 and condenser C! which was completed initially over back'contact b of relay-1GP is now completed over front-contact b of relay OR, and that contact e of relay DR provides a connection from coil" lB-to the line in parallel with contacts 0 of buttons PS. It will be also noted that if two of the buttons PS which control difierent frequencies'are inadvertently operated at the same time, a portion of the coil [1 will be short circuited by their" contacts at to prevent the generation of alternating current by the tube VT, the selection of more than one relay R3 at a time being thereby prevented;

When lamp CE becomes" lighted", the operated" button P'Sl may be released. The opening ofitscontact d terminates the delivery of the alternatingcurrent component of the" impulse, relays OR, L; LP, DR att'he oflice, and relays RI and R3" at the selected" station remaining energized due? to" the flow of unidirectional current in the" line circuit.

The operatorwi'll now press one of the buttons PF! to 2E5. Button PF! controls relayDS only; for the purpose of initiating a return indication when the signals. are" at stop. Buttons PFZ and PF3 control relays IJHS and RL'HS, respectively, to causetheselccted 'signa'rto display its permiss-ivezindicatlnn, whileBEt andlmcontroli relaysv LHS respectivelytand: relax DS in addition, tocause the selectedsignal:t'lrv mdicate proceed. j

Assuming: that button. PF-t is new relay OR will be shunted by the closinguofithe push button contact. 0 and will; release; opening its contact b in the circuit for condenser GI trolled by. the": buttons PS6 to PSlill; andi completing a tuned circuitat its baclc contacttcxfronr the upper terminal of-coil' t1, condensencii front contact 11' of relay: L and: contact a: ofi button PF I to: the terminal of coil l l marked IF, cans i'ng tube V-T todeliver current: of frequencwffitd the 1 line to energize relay DS which: turne en erg-izes relay Ll-i at the selected station. I The re lease of relay OR deenergizes relay which releases after a brief period-to terminate theim pulse, releasing relay DS Relaydeenergi zea relay LP whichreleasesafterasecond brief perl od, in turn releasing relay DR tointerruptl steady-"line current thereby releasing relay Rf, The release of relay LP extinguishes lamp-GEE indicating the return ofithe con-trot apparatus tonormal, whereupon button PF? may be released,- while' the release of relay Rt deenergizes relays R3 and Li andinitiates the-retu-m indication inrpulse of frequency fl to energize relay' K l and light the lampEl.

Assuming next that the operator'presses ton P-S-l as above described and then afterre leasing button PSI presses button-PFZ'or PFil; are impulse" of" frequency IT or I8 will be delivered to the line for the duration of= the release periodof relay'L to operate relayLHS or'RHS; whichrelay will then'be held energized over itsstick' circuitincluding front contact a of'relayTR', butrelay Ll will not be operated and no indication im pulse will be transmitted, consequentlylamp-El will remain dark;

Ifbutton" PF4 or PF5 is operated'in; place of=' button PFZ or PF3, an impulse offrequencyfl or 8 will likewise bedeli-veredto the'linefen-the be delivered to the-line for the duration ot tlle release period ofrelay LP to operate relay DS; which relay will then be held energized ovenits stick circuit includingcontact' c of relay- 133$ or RHS. In this case relay Lt isnot operated because its circuit is opened at backcontact-d of; relay LHS orR-I-IS.prior to the'closing'of front contact 12 of relayDS, and therefore noimzli'cation impulse is transmittedand lamp EI remainedarl'r; It will be seen that relay Ll is operated byrelay DS to initiate a return indication impulseonly when the operation of" relay DS isd'ueto the operation of button PM, as herei-nbefore de scribed.

It will also be seen that after the signal'IlH? or RH has been cleared, it may'be'put' manuallyto stop and the return indication initiated to light lamp El by pressing buttons PSI andPFl, or it will be put automatically tostop the lamp El lighted, due to the release of the trackrelayTR when a train governed by the signal enters section T, in which case the signal will remainat stop, due to the release of-the stick relayLHSbr RHS aftersection T is vacated; v Although I have herein shown anddescrlbli'i'l only one form of remote control system embodying my invention, it is understood that various I tact of the direct current line relay through tuned circuit elements responsive to a frequency to which the corresponding circuit elements at other stations are non-responsiva'a holding circuit for each alternating current line relay including front contacts of both line relays at that station, a plurality of control relays at each station having holding circuits controlled locally and having energizing circuits includingfront contacts of both line, relays at that static-n and also including tuned circuit elements rendering said control relays selectively responsive to alternating currents of different frequencies in said line circuit, and control means at the office for supplying direct current to the line wires for a brief period and for supplying two impulses of alternating current of selected frequencies to the line wires successively during such period to selectively energize a particular control relay at a selected station.

2 In a remote control system, an office and a plurality of stations connected by line wires, said stations being arranged in two roups, a polarized relay at each station responsive to steady current in saidline wires, the polarized relays at the stations of one group being responsive to line current of normal polarity and those at the stations of the other group to line current of reverse polarity, another line relay at each static-n responsive to alternating current of a distinctive frequency and connected to the line wires over a front contact of the associated polarized relay through tuned circuit elements responsive to a frequency to which the corresponding circuit elements at other stations of the same group are not responsive, a holding circuit for each such alternating current line relay including a front contact of the associated polarized line relay, a plurality of control relays at each station having holding circuits controlled locally and having energizin circuits includin front contacts of both line relays at that station and also including tuned circuit elements rendering each control relay at a station selectively responsive to alternating current in the line wires of a frequency different from that to which the other relays at such station are responsive, and control means at the office for supplying steady current of a selected polarity to the line wires for a brief period and for supplying two impulses of alternating current of selected frequencies to the line wires during such period to selectively energize a particular control relay at a selected station.

3. In a remote control system, an office and a plurality of stations connected by line wires, a first line relay at each station selectively responsive to current of a distinctive character, a second line relay at each station connected to the line wires over tuned circuit elements to render such relay selectively responsive to alternating wires, corresponding circuit elements at difierent stations being tuned to different frequencies, a holding circuit for each second line relay including a front contact of the associated first line relay, a plurality of control relays at each station having holding circuits controlled locally and having energizing circuits including front contacts of both line relays at that station and also including tuned circuit elements rendering each control relay at a station selectively responsive to alternating current in the line wires of a frequency different from that to which the other relays at such station are responsive, and control means at the omce for supplying current of said distinctive character to the line wires for a brief period to energize the first line relay at each station and for supplying a series of impulses of alternating current, each of a different frequency, to the line wires to selectively and successively energize the second line relay and one or more of the control relays at a selected station during such period.

4. In a remote control system, an ethos and a station connected by line wires, a line relay at the station, a selective communication channel for controlling the line relay including a source of alternating current of controllable frequency at the ofiice, said line wires, and tuned circuit elements resonant to a particular frequency, manually operable selecting means at the office including a relay for establishing said channel and means for supplying alternating current thereto of said frequency to energize the line relay, circuit means for maintaining both the oflice relay and the station line relay energized after the manually operable means is released and the delivery of alternating current to said channel is thereby interrupted, a plurality of controlrelays at said station, control channels for selectively energizing said control relays by alternating current from said source, following the release of said manually operable selecting means, each such channel including a front contact of said line relay and tuned circuit elements rendering each control relay responsive to current of a frequency different from those to which the line relay or the other control relays are responsive, manually operable control means at the office effective when operated to release said ofiice relay, and timing means responsive to the release of said onice relay effective to supply an impulse of alternating current of a particular frequency selected by said control means to said control channels to selectively energize a particular con trol relay, and to then release said line relay.

5. In a remote control system, an ofiice and a station connected by line wires, a line relay at the station, a selective communication channel for controlling the line relay including a source I of alternating current of controllable frequency at the office, said line wires, and tuned circuit elements resonant to a particular frequency, manually operable selecting means at the ofiice including a relay for establishing said channel and means for supplying alternating current thereto of said frequency to energize the line relay, circuit means for maintaining both the office relay and the station line relay locally energized after the manually operable means is released and the delivery of alternating current to said channel is thereby interrupted, a plurality of control relays at said station, control channels for selectively energizing said control relays by alternating current from said source, following the release of said manually operable selecting means, each such channel including a front contact of said line relay and tuned circuit elements rendering each control relay responsive to current of a frequency channels to energize a selected plurality of said control relays, and to then release said line relay.

6. In a remote control system, an ofiice and a station connected by line wires, a line relay and a control relay at the station, selective communication channels for controlling said relays each including a source of alternating current of controllable frequency at the office, said line wires,- and tuned circuit elements resonant to different frequencies, the channel for-the control relay to a different frequency of current from said source, means responsive to the operation of each set of selecting contacts for preparing said channels for communication between the office and the corresponding station, and for closing a circuit for said timing relay, a plurality of sets of manually operable control contacts at the office, including one set for each control relay at a station, for controlling the frequency of the current supplied by said source, and means responsive to the operation of each set of control contacts for opening the circuit for said timing relay and for rendering said source effective during the release period thereof to supply current from said source to the prepared channels of a frequency to which the corresponding control relay is responsive.

8. In a remote control system, an office and a plurality of stations connected by line wires, a

plurality of communication channels including including a front contact of the line relay; a

local holding circuit for thelcontrol relay including a back contact of the line relay, manually operable means at the ofiice for establishing said channels one at a time for brief periods and for supplying alternating current thereto to which said relays are responsive, means responsive to one operation of said'manually operable means for supplying to said channels alternating cur rents of-both frequenciesto energize the line relay and the control relay, and means responsive to another operation of said manually operable means for supplying to said channels alternating currents of only one frequency to energize the line relay only and thereby release said control relay.

7. In a remote control system, an office and a plurality of stations connected by line wires, a plurality of communication channels including said line wires and a source. of alternating current of controllable frequency, a plurality of sets of manually operable selecting contacts at the ofiice, including one set for each station, a slow release timing relay at the office, a plurality of control relays at each station each responsive selectively said line wires and a source of alternating current of controllable frequency, a plurality of sets of manually operable selecting contacts at the ofllce, including one set for each station, achain of timing relays at the office, a plurality of control relays at each station, each responsive selectively to a different frequency of current from said source, means responsive to the operation of each set'of selecting contacts for preparing said channels for communication between the oflice and the corresponding station and for energizing the relays of said chain, a plurality of sets of manually operable control contacts at the oilice, including one set for each control relay at a station, fc-r controlling the frequency of the current supplied by said source, and means responsive to the operation of each set of control contacts for releasing said timing relays one at a time in order, and means effective during the release period of said timing relays for supplying current from said source to difierent ones of said prepared channels one at a time to successively energize a plurality of said control relays by currents of different frequencies, dependent upon which set of control contacts has been operated. ANDREW J. SORENSEN. 

